Permanent magnet latching type vacuum relay



Dec. 27, 1966 v. E. DE LUcaA ETAL 3,295,080

PERMANENT MAGNET LATCHING TYPE yVACUUM RELAY Filed June 8, 1965 WWK@FNK@

United States Patent O 3,295,(i80 PERMANENT MAGNET LATCHENG TYPE VACUUMRELAY Victor E. De Lucia, Santa Monica, and Bruce C. Nieland,

Los Angeles, Cali.; said Meland assigner to Terr Laboratories, Inc., LosAngeles, Calif., a corporation of California Filed Suns 8, 1965, Ser.No. 462,264) 2 Claims. (Cl. 335-153) The present invention relates tohigh voltage vacuum relays; and it relates more particularly tominiature, highvoltage vacuum relays which are actuated from one stateto another by -brief pulses, and which do not require a steady ow ofcurrent to be maintained in any particular state.

As is well known, for usual prior art relay operations, a relay coil isenergized by a continuous current to establish the relay contacts in aparticular state, and when the current is terminated, the relay contactsare returned, usually by spring action, to their original state.

Other types of prior art relays are provided with latching means,whereby, once the relay is energized, its contacts are maintained in theparticular state to which they were actuated, even after the energizingcurrent is terminated. However, this latter type of relay still requiresthat the applied current which actuates the relay be so applied for asufficiently long interval to per-mit the relay contact to assume thepa-rticular state, before the relay can be latched.

The above mentioned requirement of a continuous ow in the usual type ofprior art relay, and slow response in this type of relay and in thelatching type of relay, has seriously limited the use of mechanicalrelays, especially in high speed electrical circuits.

The use of high voltage vacuum relays is widespread in manyapplications, including space vehicles, missiles and the like. However,the use of this type of relay, likewise, has been limited beca-use ofthe slow response time, and also beca-use of the requirement for acontinuous current flow through the relay coil in order to maintain therelays in their energized condition.

The high voltage vacuum relay is advantageous in that its contacts arehoused in au evacuated envelope and are not'subiect to degradation dueto arcinlg, which would normally occur Iif the contacts were operated inthe usual atmosphere.

As indicated above, the application of the high voltage relay, and itsfield of usefulness, would be vastly increased if it were not for thefact that, prior to the present invention, the relays for many Ipurposeswere not sufficiently fast in their response. Moreover, such relaysrequired continuous current, rather than brief pulses, in order toenergize their operating coils.

The concepts of the present invention, which provide a vacuum relaycapable of responding to extremely brief pulses, enables the relay ofthe invention to be constructed with relatively high ampere-turns forincreased sensitivity. Moreover, this is achieved without the problemsencountered in the prior yart relay of this particular type, in whichcurrent is drawn through the energizing coil for prolonged periods oftime, when the relay is energized.

An object of the present invention, therefore, is to provide animprovedhigh voltage vacc-um relay which exhibi-ts bistablecharacteristics and which may be pulsed by extremely brief pulses fromone stable state to the other.

Another object of the invention is to provide such an improved relaywhich is capable of responding to such extremely brief pulses, since itslatching operation does not depend upon actual armature movement tobecome effective. Rather, a brief pulse applied to the relay im-3,295,953@ Patented Dec. 27, 1965 ice rnediately changes the state ofthe remanent magnetization of an element included in the relay, and thatparticular element subsequently acts either to attract or repel apermanent magnet armature, so as to establish the relay in one stablestate or the other.

Another object of the invention is to provide such an improved highvoltage vacuum relay which utilizes a pivoted armature, the armaturehaving no associated springs or other resilient members, so thatproblems of mechanical resonances Iare obviated.

Yet another object of the present invention is to provide an improvedhigh volta-ge vacuum relay which utilizes a low mass, low inertiaarmature and which does not exhibit any tendency to spurious operation,even in the presence of excessively high vibratory conditions.

The improved relay of the present invention may utilize, for example, abistable magnetic element which may be composed, for example, of amagnetic alloy referred to as Remendurf This is a vanadium, cobalt, andiron alloy recently developed by the Bell Telephone Laboratories. Themagnetic alloy is described, for example, in the Bell Laboratory Recordfor March 1964.

Remendur is composed, for example, of 2.5% vanadium, 49% cobalt, and48.5% iron. This magnetic alloy is capable of exceedingly high values ofremanence, for example, up to 21,500 gauss. This magnetic alloy exhibitsa unique combination of magnetic and mechanical properties, ideallysuited for the purposes of the present invention. The alloy has, forexample, an essentially square hysteresis loop for efficient switchingoperation. lt also hasa comparatively stable coercive force in the rangeof 20-60 cersteds. It has essentially isotropic magnetic properties, anda high Curie temperature.

Moreover, the magnetic alloy, Remendur, has suiiicient malieability `andductility to permit it to be processed into thin strips. Moreover,Remen-dur can be easily electroplated in order to enhance its electricalconductivity. Finally, the alloy responds to simple heat treatment.

When an element is formed of a bistable magnetic material as Remendur,and when a coil magnetically coupled to the element is successivelypulsed :by electrical pulses of opposite polarity, the element is causedto assume corresponding first and second remanent magnetic conditions.

For example, when the aforesaid element is pulsed so as to change itsmagnetic remanent condition from one polarity to another, the change isinstantaneous, as noted above, and the change may be produced by anexceedingly brief electric pulse. Thereafter, in its normal responsetime, the relay armature responds to the changed remanent condition ofthe element to be attracted or repelled thereby so as to change thestate of the relay contacts. Then, the relay remains in its latterstate, until an opposite polarity pulse changes the remanent conditionof the element back to its original polarity.

A permanent magnet is employed in the embodiment of the invention to hedescribed, so as to establish the armature with a selected magneticpolarity. The permanent magnet preferably is positioned outside theevacuated envelope, and it may be replaceable to provide differentmagnetic strengths, as desired.

Moreover, the external positioning of the permanent magnet enables theevacuated envelope to he subjected to usual high vacuum and hightemperature outgassing procedures without the permanent magnet being inthe assembly. This prevents degradation of the permanent magnet whichwould occur if it were mounted within the envelope during the outgassingoperation.

The features of the invention which are believed to be new are set forthin the claims. The invention itself, however, together with furtherobjects and advantages thereof, may best be understood by reference tothe following description, when the description is taken in conjunctionwith the accompanying drawing, in which:

FIGURE 1 is a plan view of an improved vacuum relay constructed inaccordance with the concepts of the invention; and

FIGURE 2 is a fragmentary side sectional View of the assembly, takenessentially along the line 2 2 of FIG- URE 1.

The relay assembly, as shown in the drawing, includes an envelope l0,This envelope, in accordance with the usual vacuum relay procedure, isevacuated, so that the relay contacts operate in a vacuum, for reasonswell understood to the art.

A rst terminal pin 12 is sealed in one end of the envelope llt), theenvelope having an essentially cylindrical configuration in theillustrated embodiment. This terminal pin 12 may be formed of anysuitable electrically conductive material, such as tungsten.

A rod ld is mounted on the inner end of the pin 12, and this rod isattached to an element 16. The element i6 may be composed of Remendur,or equivalent material, so as to exhibit the aforesaid bistable remanentmagnetic properties. The rod 14 is also electrically conductive, and itsupports the element 16 rigidly within the envelope itl. An appropriateelectrical contact 18 composed, for example, of tungsten, is affixed tothe inner end of the element 16.

An electrical coil 20 is mounted on the envelope 10 in position tosurround the element 16, and the coil is magnetically coupled to theelement. The coil 2t) responds to brief electrical pulses selectively tochange the magnetic remanent condition of the element 16 from onemagnetic polarity to the other.

A further terminal rod 22 is sealed to the opposite end of the envelopeMl. This latter terminal rod may be composed, for example, of Kovar. Amember 24 composed, for example, of soft iron, is welded, or otherwiseaffixed, to the inner end of the rod 22, the member 24 being positionedwithin the envelope itil.

An armature 26 is positioned in the envelope 1t) to make selectivecontact with the element 16. The armature has a contact 28 composed, forexample, of tungsten. The contact 23 on the armature 26 engages thecontact 1.3 on the element 16, when the armature 26 is moved against theelement 16.

The armature 26 is supported by means of a rod 30 on the end of themember 24, the rod 3@ being pivoted to the member 24 by means of anappropriate pivotal coupling 32. The armature 26 and rod 30 may both becomposed of an appropriate magnetizable material, such as soft iron.

In addition, a nonmagnetic rod 34 is rigidly fastened to the inner endof the member 24, and the rod 34 extends along the length of theenvelope 1t) to the point at which the armature 26 overlaps the elementT6.

A magnetic member 36 is mounted on the end of the rod 34, and thislatter member may be composed of an appropriate magnetizable material,such as soft iron. As shown in the drawing, the member 36 overlies theend of the armature 26, so that armature engages the member 36 when itis displaced from the element 16.

A lpermanent magnet atl is removably mounted in the terminal 22, asshown, and externally of the envelope 1t), for the reasons explainedabove.

It will be appreciated that when an electric pulse of a first polarityis passed through the coil 20, the element 16 assumes a first magneticremanent condition, so that it attracts, for example, the armature 26.The armature 26, of course, is established in a permanent magnetic stateby the permanent magnet 4t). The attraction of the element 16 issufcient to cause the armature 26 to move .away from the member Then,when a Amagnetic pulse of opposite polarity is "I passed through thecoil 2t), the element 16 assumes the opposite magnetic remanentcondition, so that it repels the armature 26, and causes it to moveagainst the member 36.

The magnetic attraction between the armature 26 and the member 36 issufficient, so that the member 36 holds the armature against anymovement, even in the presence of excessively high vibratory conditions.1n this manner, spurious closures of the contacts 28 and 16 areprevented.

Appropriate electrical connections can be made to the terminals 12 and22; and a contact is established between these two terminals, wheneverthe relay is energized so as to draw the armature 26 down intoengagement with the element 16.

The fact that the armature 26 is pivotally mounted in the envelope lit,without the use of springs, or the like, renders the relay of theinvention devoid of unwanted mechanical resonances.

Also, the member 36 provides a simple means of holding the pivotedarmature 26 in a stationary condition in the envelope 10, whenever therelay is in a state such that the contacts 18 and 28 are open.

The relay of the present invention has been found to operate with a highdegree of efficiency, even in exceedingly high voltage circuits. It has-been found that the magnetic forces provided by the element 16 andarmature 26 are sufiicient to overcome any counteracting electrostaticforces due to high voltage which are or may be developed in the relay,when the contacts 28 and 18 are open.

While a particular embodiment of the invention has been shown anddescribed, modifications may be made. It is intended in the claims tocover all modifications which come within the spirit and scope of theinvention.

What is claimed is:

ll. A vacuum relay including: an evacuated envelope; a first elongatedmember of magnetizable material positioned in said envelope; a furthermember of magnetizable material mounted at one end of said envelopecoextensive with said first elongated member and extending through saidenvelope; permanent magnet means mounted externally of said envelope andmagnetically coupled through said further member to said rst elongatedmember to establish said first member in a particular magnetic state; asecond elongated member positioned in said envelope for selectiveengagement with said first member and being composed of a materialcapable of exhibiting first and second distinct states of remanentmagnetization; means for pivotally mounting said first elongated memberat one end to said further member; an electric coil magnetically coupledto said second member and responsive to electrical pulses of oppositepolarities for changing the state of remanent magnetization of saidsecond member wheneby the magnetic eld thereof selectively aids andopposes the magnetic field of said first member; a member ofmagnetizable material; and means for supporting said last namedmagnetizable member in said envelope in position to be engaged by thefree end of said first elongated member and magnetized thereby when saidfirst elongated member is out of engagement with said second elongatedmember, said last named magnetizable member serving to hold said firstelongated member against vibratory movement when so engaged thereby.

2. The vacuum relay defined in claim 1 in which said permanent magnet isremovable.

References Cited by the Examiner UNITED STATES PATENTS 2,957,961 10/1960Juptner 200-87 3,059,075 10/1962 Peek ZOO-87 BERNARD A. GILHEANY,Primary Examiner. I. J. BAKER, Assistant Examiner.

1. A VACUUM RELAY INCLUDING: AN EVACUATED ENVELOPE; A FIRST ELONGATEDMEMBER OF MAGNETIZABLE MATERIAL POSITIONED IN SAID ENVELOPE; A FURTHERMEMBER OF MAGNETIZABLE MATERIAL MOUNTED AT ONE END OF SAID ENVELOPECOEXTENSIVE WITH SAID FIRST ELONGATED MEMBER AND EXTENDING THROUGH SAIDENVELOPE; PERMANENT MAGNET MEANS MOUNTED EXTERNALLY OF SAID ENVELOPE ANDMAGNETICALLY COUPLED THROUGH SAID FURTHER MEMBER TO SAID FIRST ELONGATEDMEMBER TO ESTABLISH SAID FIRST MEMBER IN A PARTICULAR MAGNETIC STATE; ASECOND ELONGATED MEMBER POSITIONED IN SAID ENVELOPE FOR SELECTIVEENGAGEMENT WITH SAID FIRST MEMBER AND BEING COMPOSED OF A MATERIALCAPABLE OF EXHIBITING FIRST AND SECOND DISTINCT STATES OF REMANENTMAGNETIZATION; MEANS FOR PIVOTALLY MOUNTING SAID FIRST ELONGATED MEMBERAT ONE END OF SAID FURTHER MEMBER; AN ELECTROC COIL MAGNETICALLY COUPLEDTO SAID SECOND MEMBER AND RESPONSIVE TO ELECTRICAL PULSES OF OPPOSITEPOLARITIES FOR CHANGING THE STATE OF REMANENT MAGNETIZATION OF SAIDSECOND MEMBER WHEREBY THE MAGNETIC FIELD THEREOF SELECTIVELY AIDS ANDOPPOSES